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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

26362 results found.

  1. GRB061202: Swift/UVOT Upper Limits
  2. GRB 061202, Swift-BAT refined analysis
  3. GRB 061202: Swift detection of a burst
  4. GRB 061201: VLT optical observations
  5. GRB 061201: Initial UVOT Observations
  6. GRB 061201, Swift-BAT refined analysis of the SHB
  7. GRB 061201: Swift detection of a short hard burst
  8. INT+WFC observations of GRB 061126
  9. Swift XRT on-board boresight update
  10. GRB 061126: optical observation
  11. GRB 061126: Tautenburg afterglow observations
  12. GRB061126: Optical afterglow observations from MIRO
  13. GRB061126: Optical afterglow observations from MIRO
  14. GRB 061126 : SDSS Pre-Burst Observations
  15. GRB 061126: Swift-XRT refined analysis
  16. GRB 061126: Swift/UVOT Observations
  17. GRB 061126, Swift-BAT refined analysis
  18. GRB 061126: Early Detection of the IR Afterglow
  19. GRB 061126: Swift/UVOT Afterglow Detection
  20. GRB 061122: Candidate Optical Afterglow
  21. GRB 061121: Ep,i - Eiso correlation
  22. GRB061122: Swift/UVOT Optical Observations
  23. GRB061121: P60 Observations
  24. Radio detection of GRB 061121
  25. GRB061122: Swift-XRT position
  26. INTEGRAL results on GRB 061122
  27. Swift-BAT trigger 239987 is not a GRB
  28. GRB 061121: Swift/UVOT Observations
  29. GRB 061121: Swift-XRT Team Refined Analysis
  30. GRB 061121, Swift-BAT refined analysis
  31. GRB061121, optical observation
  32. GRB 061121: Optical observation at the KANATA 1.5m telescope
  33. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  34. GRB 061121: Swift detection of a bright burst with an optical counterpart
  35. GRB 060605: NIR Observations
  36. GRB 050915B: optical afterglow
  37. Swift-BAT triggers 238544 and 238546 are not GRBs
  38. Swift/UVOT Upper Limits for GRB061110b
  39. Swift/UVOT Upper Limits for GRB061110a
  40. GRB 061110B, Swift-BAT refined analysis
  41. GRB061110B: Optical observations at Crni Vrh
  42. GRB 061110A: Swift XRT refined analysis
  43. GRB 061110A, Swift-BAT refined analysis
  44. GRB 061110B: TAROT Calern observatory optical observations
  45. GRB 061110B: Swift detection of a burst
  46. GRB 061110: Candidate confirmed
  47. GRB 061110 : Optical afterglow candidate
  48. GRB 061110: ROTSE-III Optical Limits
  49. GRB 061110: Swift detection of a burst
  50. GRB061110A - Optical Non-detection
  51. GRB 061109: optical observation
  52. GRB 061109: TAROT Calern observatory optical observations
  53. GRB 061027: TAROT La Silla observatory optical observations
  54. GRB 061028: Swift/XRT Astrometry Correction
  55. GRB 061102: Swift/UVOT Magnitude Upper Limits
  56. GRB 061102, XRT refined analysis
  57. GRB061102B: Super-LOTIS observations
  58. GRB 061028: Optical R passband observations
  59. GRB 061102B: Swift detection of a possible burst
  60. GRB 061102, Swift-BAT refined analysis
  61. GRB 061102: Swift detection of a burst
  62. GRB 061028: VLA Observation
  63. GRB 061004: Swift/XRT Astrometry Correction
  64. GRB 060801: Swift/XRT Astrometry Correction
  65. GRB 061028: Futher P200 Observations
  66. GRB 061028: P200 Observations
  67. GRB 061028: SARA upper limit
  68. GRB 061028: z band imaging
  69. GRB061028: XRT refined analysis
  70. GRB 061028: Swift/UVOT Observations
  71. GRB 061028, Swift-BAT refined analysis
  72. GRB 061028: TAROT Calern observatory optical observations
  73. GRB 061028: Swift detection of a burst
  74. GRB 061027, Swift refined analysis of a possible burst
  75. GRB 061027: Swift detection of a possible burst
  76. GRB061025: Swift XRT refined analysis
  77. GRB061025: Swift/UVOT observations
  78. GRB 061025: REM observations
  79. GRB 061025: ROTSE-III Optical Limits
  80. GRB 061025: a long GRB detected by INTEGRAL
  81. Swift XRT boresight update
  82. GRB 061021: Swift/UVOT Observation
  83. GRB 061021, Swift-BAT refined analysis
  84. GRB 061021: Swift detection of a burst
  85. GRB061019: optical observations
  86. GRB 061019: SARA upper limit
  87. GRB 061019: Swift/UVOT upper limit
  88. GRB 061019: SMARTS afterglow confirmation
  89. GRB061019: Swift XRT refined analysis
  90. GRB 061019, Swift-BAT refined analysis
  91. GRB 061019: TAROT La Silla observatory optical observations
  92. GRB 061019: REM K-band candidate afterglow
  93. GRB 061007: Second Epoch ATCA Radio Observations
  94. GRB 061007: Suzaku/WAM observation of the prompt emission
  95. GRB 061006: astrometry-corrected XRT position
  96. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  97. GRB 061007: ATCA Radio Observations
  98. GRB061007: Swift UVOT followup observations
  99. GRB 061006: optical afterglow
  100. GRB 061007: OA fading and VLT redshift

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